Lennox 12F19 Flame Sensor

The Lennox 12F19 Flame Sensor is a critical safety component designed for precise flame rectify detection in residential and commercial gas-fired heating systems. This genuine OEM part is engineered to monitor the burner's pilot or main flame, sending a continuous microamp signal to the furnace control board. If the 12F1901 furnace sensor fails to detect a flame, it immediately signals the gas valve to shut down, preventing hazardous gas accumulation. Built with high-grade 18-gauge wire and a durable ceramic insulator, this flame rod replacement ensures long-term resistance to high-temperature oxidation and carbon buildup.

As a direct replacement for the obsolete Lennox 12F1901, this sensor features a 0.094" x 0.922" probe and a standard 1/4" male spade terminal for seamless integration into existing wiring harnesses. It is a vital HVAC furnace part for maintaining the ignition sequence in Lennox G12, GCS, and various other high-efficiency series. For service technicians, replacing a fouled or cracked sensor with this OEM Lennox flame sensor eliminates intermittent "no-heat" calls caused by failed flame rectification and ensures equipment operates at peak safety specifications.

Key Benefits

• Direct OEM Compatibility: Specifically designed to replace the Lennox 12F1901 without modifications to the mounting bracket or electrical connections.
• Heavy-Duty Construction: Features 18 GA wire and a high-temperature probe to withstand the intense heat of the domestic and commercial burner assembly.
• Safety-First Operation: Prevents gas valve opening in the absence of a verified flame, protecting the heat exchanger and property.
• Universal Terminal: Equipped with a 1/4" spade terminal for quick attachment to the existing ignition control lead.
• Optimized Signal Strength: Ensures consistent microamp readings to prevent nuisance tripping and furnace lockout.

Common Questions

Is the 12F19 the same as the 12F1901?
Yes, the Lennox 12F19 is the current catalog number and is functionally identical to the 12F1901 flame sensor. It is the direct manufacturer-recommended replacement.

What are the symptoms of a failing flame sensor?
Common indicators include the furnace lighting for several seconds and then shutting off (short cycling), or the control board displaying a flame failure lockout code. If the flame rod is soot-covered or the insulator is cracked, it requires immediate replacement.

Which models use this specific sensor?
This part is widely used across Lennox residential furnaces and commercial packaged units, including the G12 and GCS series. Always verify the part number against your unit's specific parts list or wiring diagram.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.